DE2239137A1 - METHOD AND DEVICE FOR INTERMITTING CHECKING OF A WEIGHING AND DOSING DEVICE - Google Patents

Description

PATENT LAWYERS

DR. INC. A. VAN DERWERTH DR. FRANZ LEDERER Al HAMBURG 90 8 MUNICH 80 WlLSTOItI ¹ ER »Τ«. 33 TtL. 10411) 77 08 61 LUCILE-CRAHN-STf ?. 22 TEL. (06 11) 47 29

Applicant; ·

I. I. Smidth & Co. A / S

Vigerslev All 77

Copenhagen '- Valby / Denmark

Method and device for intermittent checking of a weighing and dosing device

Continuously working weighing and dosing devices for example according to DT-Pat. P 19 17 570.3 ·, become on a large scale in plants for treatment, distribution and conveying of masses of material were used and were found to be very suitable for the continuous measurement of a current a material mass by weighing or for dosing this material found on a device, for which it it is very important that the dosage can be regulated according to requirements.

Such devices for continuous weighing and dosing however, they are not suitable for accurate weighing like static weighing devices, which are adapted to determine the weight of a particular quantity of material.

./2 309808/0930

2239Ί37

Static vibrating devices are therefore very suitable for performing effective control of the accuracy of continuously operating equipment. This is preferably done by test weighing the amount of material mass produced by the continuous working weighing and dosing device runs through for a certain time, with the help of a precisely weighing, static weighing device performed, being checked. whether an identical weighing result is achieved

It is important that the test weighing takes place without disturbing the normal operation of the Y / ye weighing or dosing device. A typical example is the weighing of cement raw meal for a rotary kiln for cement burning

Known test weighing techniques suffer from various disadvantages, in particular with regard to the requirement that the test weighing must not disrupt normal operation of the system; the invention is therefore based on the object to overcome these disadvantages.

The invention is a method for intermittent Check whether a continuously working weighing and dosing device is set correctly for a material mass is, in which during normal operation material is introduced into a closed circuit in which the material is moved circumferentially, with a part of the material from the circle addition to a continuously working weighing or Dosing device is fed to the extent with which the device operates, and wherein the remainder of the material is passed through a memory and v / pus circulates in a circle; this procedure provides a Interruption of the supply of the mass of material to the closed circuit and a determination of the extent at which the continuous working weighing or dosing device material

30980/0930

takes from the closed circle, and thus de.s operational dimensions the device by determining the decrease in the weight of the material in the closed ice within " a known time

The memory can be a weighing container that is used to determine the decrease in material weight is weighed in the closed loop, or it can be the entire closed loop Circle to be weighed *

Preferably, the closed loop includes substantially one vertical conveyor, which conveys the material up, and the rest of the material runs through a feeder and is returned to the bottom of the conveyor · The mass of material can be intermittent as required to the closed circuit, preferably also to the bottom of the conveyor, for example from a "silo" · With this arrangement, the desired control takes place without disrupting the operation of the weighing or dosing device instead, and "all incorrect quotas of the weighing or dosing device are detected.

A device for carrying out the method has ■ a closed circuit for the material mass and controllable means for supplying the mass of material to the closed loop, a closed loop conveyor, by means of which the material can be fed to a feed head is, through which it can be fed to a weighing or dosing device, a chute with a memory, over the overflowing Material can be returned from the feed head to the bottom of the conveyor, means for weighing at least the in the part of the closed circuit forming the storage material and the output of the means for simultaneous control of the supply of the material mass to the closed circuit, so that when the material

309808/0930

Weight to a predetermined lower limit the material supply started on the closed circuit and when the material weight rises to an upper limit, the material supply to the closed circuit is terminated, and an indication of the weight of at least the ^ the part of the closed circuit forming memory,., located material, so that the decrease in the weight of the material in a closed circuit can be determined in a given time.

Preferably the lower end of the conveyor protrudes into the supply container, where it can be loaded with material mass, with both the controllable means, the freshness Feed the material mass into the closed circuit and also empty the chute from the storage tank into this supply container.

To further improve the accuracy of the device, the memory, the supply container, the continuously working weighing or dosing device and the conveyor installed in a common frame, which rests on the weighing elements, the. work as a weighing device.

The device can be adapted to the use of multiple weighing or metering devices, in which case the storage in the closed circuit is connected in parallel to a container, which is used for receiving and passing through of material mass outside the test intervals and means for including the memory in the system for the individually executed test of several continuously working weighing and dosing devices are provided.

The drawings show exemplary embodiments of a device for carrying out the method according to the invention

309808/0930 ^{: t / 5}

shown; show it:

Fig # 1 is a schematic view of a static metering device with means for controlling their weighing accuracy ι

Fig. 2 shows a modification of the Pig device. 1 and

Fig. 3 is a schematic representation of a system with two dosing devices with common means for controlling the weighing accuracy, one each Contraption·

The device shown for carrying out the invention Process is a system for use in the dosing of cement raw meal for a rotary kiln into cement. burn, , -.-.'.

According to FIG. 1, the material, here raw cement meal, flows out of one Silo 1 through floor outlets 2, 3 and 4 with valves 5, 6 and 7 to a horizontal screw conveyor 8, one of which Chute 9 leads to a supply container 10 From this the goods are removed with the help of a vertical conveyor 11, from its upper end aμs a slide .12 to a supply head in the form of an overhead or covering. horizontal auger 13 which carries the bulk of the material a weighing or dosing device 14 of known type with an outlet 15 ', through which the material in.Rrichtung a rotary kiln (not shown). The rest of the material leaves the screw 13 via a chute 16 into which 'a weigh bin 1? is built in · Another small one Small excess. Guts consisting of inevitable uber-r run well off the weighing: and dosing device 14 is in an overflow funnel18 and also the weighing hopper I? fed · The material leaves the weighing container 17 durch.eine bottom outlet 19 with a valve 20 and flows through the lower part of the chute 16 to the supply

30980170930 ^{# / 6}

ßungsbehälter 10 back.

The weighing container 17 rests on weighing elements 21, which nit an instrument 22 in connection 3, which shows the weight of the Gut3 in the weighing container. The weighing elements 21 give signals to the opening and closing of the outlet valves 5 »6 and 7 of the silo depending on the weight of the Guts in the weighing container 17.

-The supply container 10 is with a level indicator

23 equipped with a signal to close the exhaust valve 20 of the weighing container is able to dispense when the supply container is full.

Another level indicator is located in the supply container 10

24 slightly higher than the indicator 23 provided. Of the Level indicator 24 is able to give a signal to close the outlet valves 5 »6 and 7 of the silo for the supply of fresh, i.e. further, goods to the supply container, when the level of the good reaches the indicator 24.

Since the weighing container 17 rests on weighing cells 21, the necessary, infinitesimal up and down movements must be compared to the stationary environment with which it is connected, be possible without obstacles. Therefore, the bottom outlet 19 is as Bellows formed; an identical bellows 25 is built into the slide. .

The overflow funnel 18 is formed integrally with the weighing container 17 and therefore moves together with it. A casing 1P ^M is fixedly or rigidly connected to the weighing container 17, which surrounds the container and is equipped with means (not shown) for filling the casing with water and for emptying it again, if desired Checking the accuracy of the instrument 22 and

309808/0930 * ^{/ 7}

of load cells 21. The weight of the casing the amount of water drained off is shown with the difference in display of the instrument 22 between water-filled and empty Sheath 17 '' compared. Unless there is a difference between these measurements "exists, the instrument 22 must be adjusted.

During normal operation of the system, the vertical conveyor 11 conveys an amount of material per unit of time which corresponds to 120 to 125% of the amount of material to be delivered per unit of time from the weighing or metering device 14 through the outlet 15 to the rotary kiln. If the amount of material flowing to the supply container 10 exceeds this value, the level indicator 24 causes the outlet valves 5, 6 and 7 of the silo to close. The 120 "to 125% of the material is conveyed by the vertical conveyor 11 into the weighing or dosing device 14, which is set for the handling or treatment of those to be led to the rotary kiln. The remaining 20 to 25 % of the material flow over the Slide 16 into the weighing container 1? And thus then to the supply container 10, in which the level of the goods fluctuates between the level of the level indicator 23 and a lower level, when the level indicator 23, when triggered, causes the outlet valve 20 of the weighing container to close The product level in the supply container 10 rises to the level of the higher level indicator 24, the supply of fresh, ie further, material from the silo 1 is interrupted or shut off as indicated.

The weighing elements 21 can, for example, be set in such a way that they send a signal to close the valves 5, 6 and 7 for the supply of fresh, i.e. further, material to the supply container 10 when the weighing container 17'40't of the property contains. The measurement can be carried out using the Instruments 22 checked or carried out. If that

309808/0930 ^{t / Q}

Weight of the gate in the meadow container then to maybe 20 t drops, the weighing elements cause valves 5, 6 and 7 to reopen. In this way the amount of goods in the weighing container can vary between 20 and 40 t. ■ ■ ·

If the accuracy of the weighing and dosing device 14 is to be checked, the point in time at which the maximum quantity of 40 t (read on the instrument 22) is contained in the weighing container 17 is first waited for; thereafter, the exhaust valves 5 _f 6 and 7 of £> Ilos be closed. To ensure that the screw 8 and the outlet 9 are empty or empty, the operator waits a little longer, for example until the instrument 22 shows 35 t, before reading the weight of the weighing or dosing device and starting a stopwatch. From this point on, the weighing or dosing device only receives goods from the closed system, which is shown to the right of the silo 1 in the drawing. When the instrument shows 20 t and just before the silo's outlet valves are subsequently opened again, the weighing or dosing device and the stop watch are read again. If the weighing or dosing device shows that 15 t has passed through during the check, it is correctly set, otherwise it must be readjusted.

During the "review, the closed system will not be Well abandoned from the outside because the outlet valve 20 of the weighing container 17 as a result of the response of the level indicator 23 is kept open during the interval, whereby the continuous material supply to the weighing or dosing device is possible. The 15 t to that of the weighing container has been relieved during the meal, therefore inevitably have the meadow or do-

309808/0930 ^{f / 9}

siervorrichtung happened in the direction of the rotary kiln.

FIG. 2 shows a system that is very similar to the system of FIG. 1, the components of which are denoted by the same reference numerals ″ insofar as they correspond to components of FIG. 1.

The main difference is that the weighing container 17 and the overflow funnel 18 are not only supported on the weighing elements 21, but that part of the rest of the device, namely parts 10 to 16, 19 »20, 23 and 2 ² I-, are also supported on the yoke elements.

These parts are held together with the aid of the frame shown in the figure in the form of steel girders 26, 27, 28 and 29. The carrier 28 rests on the weighing elements 21, and these are thus grounded by the weight of all of them Parts and the amount of raw meal contained in the entire system are burdened.

While in the system of FIG. 1 two flexible connections in the form of the bellows 19 and 25 are provided, is at the system of FIG. 2 only requires such a flexible connection, and this is achieved in that the slide 9 is designed as a bellows.

Finally, the bucket holder 17 is not in this case Equipped with a 17 '' water jacket.

The advantage of the system of FIG. 2 is that care is taken that it does not earth as expected can that the amount of located in the conveyor 11 and in the other connecting parts between the individual parts of the system Guts exactly the same at any given time

309008/0930

is. In this way there is more precise control accessible.

Fig. 3 shows a system by means of which it is possible to use one and the same control or monitoring device alternatively in connection with two continuously working weighing or To use dosing devices without an interruption normal operation of the rotary kiln or the like. entry, with which the weighing or dosing devices are connected.

This system is also broadly analogous to that of the Pig. 1 and 2 formed; the reference symbols are therefore so far possible the same. Thus, in Fig. 3, the silo is again denoted by 1, but on which only one bottom outlet opening is provided, in which a valve 5 is installed. The valve 5 opens or interrupts the supply to the horizontal Screw conveyor, which is only shown here as line 8.

Since two rotary kilns are to be fed with raw meal, two weighing or dosing devices 14a and 14b, one for each oven, intended. They are supplied with raw meal from a separate vertical conveyor 11a and 11b, and two horizontal ones Screw conveyors, shown as lines 13 a and 13 b, each lead the raw meal to a separate weighing or metering device to.

In the systems of FIGS. 1 and 2, the raw meal passes the weighing container 17 on its way to the rotary kiln, regardless of whether a weighing control or check is carried out or nichb. This is when planting the fit. 3 different; because there the raw pipe is only then passed through the Y / laying container 17, if an exam wagon finds it, where to go total raw meal outside the periods which is passed through a by-pass container 17 '.

./TI 309808 / 0Ö3Ö '

The excess raw meal arriving along the paths 16a or 16''b meets on its V / eg a switching device 30a or 30b, each of which can be in one of two positions, ie in a left or a right position controlled so that either both in the left position or one in
the left and the other are in the right position; however, both cannot be in the right position. When both are in the left-hand position, the excess raw meal is fed from both 14-a and from 14b to the by-pass container 17 "as can be seen
it leaves again through its bottom, from where it enters a pipe 16 'into which a valve 20 is installed. On its further path, the goods arrive in a supply container 10 ′ of the same type as the supply container 10
of the other two figures. While the vertical conveyor 11 protrudes into the supply container 10 according to FIGS. 1 and 2 and picks up the raw meal from it, the raw meal from the supply container 10 'according to FIG
31b. Each of the V / ege 3 "Ia and 31b has a separate valve 32a or 32b. The valves are either both open
or one valve is open and the other valve is closed; however, both valves are by no means closed at the same time.

In the upper part of the by-pass container 17 ″, a level indicator 33 is provided, which emits a signal when the level of the goods reaches the upper limit. In this case,
the valve 5 * closed, whereby the level of the good in the
Container 17 'is prevented from rising further.

Under normal operating conditions, ie without test weighing, the raw meal moves from silo 1 as its starting point along the following path: 1, 5, 8, 10 ', 31
(a and b), 11 (a and b), 13 (a and b) y 14 (a and b),

309808/0930

./1

15 (a \ ind b) to one or both rotary kilns (not shown) in weighed amounts determined by the setting of the weighing and dosing devices 14a and 14b are. However, as indicated in connection with FIG. 1, the quantity delivered by 10 'is greater than that normally amount to be delivered to the ovens; and from both 14a and 14b an extra amount of raw meal is added along the Lane 16 (a and b), 30 (a and b), 16 '(a and b), 1' / ', 20', 10 'moved; this amount is added to the amount that passes from 1 through 10 and lanes 31a and 31b tracked · In the same way as in the case of the supply container 10 of FIGS. 1 and 2, level indicators 23 ' and 24 'by closing the valve 20' ensure that the Good level in the supply container 10 'does not rise too high.

If a check is desired as to whether, for example, the weighing and metering device 14a is metering correctly, it can this can be done with the aid of the weighing container 17 and the operating system connected to it. The same thing can be carried out for the weighing and dosing device 14b, but only for one of the two devices at a time specific point in time, and this procedure can be carried out at any time by actuating a switch a or b depending on of which of the two devices 14a and 14b is to be checked.

When the review is initiated, the food container contains 17 Good up to level H (upper level). The pointer of the instrument 22 is then on the rake H, at which position certain contacts are closed in an automatic electrical system; the tracks of the control circuit are shown schematically with dot-dash lines.

./13 309808/0930

The supply container Ί0 belonging to the weighing container 17 is suspended under the weighing container with the aid of steel suspensions 34 ·. ·

When the Rohinehl from the weighing container 17 at its lower End runs out, it passes through the Y-valve 20 down into the supply "he keeps 10 and thus in the tube 16, with another valve on its way

35 happened. At the end of the tube 16 is a switching device 36 provided. Assuming the valve is 35 open, enables the switching device 36, when it is in its left position, that the raw meal into the pipe 31t> and from there to the vertical conveyor .1Ib or, with the switching device in its right-hand position, into the tube 31a and then to the vertical conveyor 11a arrives. When the switching device

36 is in its left position, the valve 32b is closed, and when the switching device is in is in its right position, the valve 32a is ge. closed.

The weighing container 17 is the same as the how it holds 17 Fig. 1 and 2 and supported on the weighing elements 21, the are electrically connected to the instrument 22. The weighing container 17 and the supply container 10 thus lead infinitesimal movements under the influence of the weight with which they are loaded at a given point in time; this requires the provision of flexible connections between the weighing bin 17 and other means by which it is connected (compare the description relating to FIG. 1). The flexible connections exist as schematically indicated in bellows 25a, 25 * b and 9

3098 06/0 33

It is assumed that the weighing and dosing device 14a is to be checked. At the moment when this process is initiated, both switching devices 30a and 30b are in their left-hand positions. The valves 20 and 35 are closed. The switching device 36 can be in either of its two possible positions, which depends on which of the two devices 14a and 14b was last checked. The valve 5 is open unless the by-pass container 17 'is filled to its capacity. The valve 2O ¹ and the valves 32a and 32b are open.

Depression of contact a has the following effect:

1. The switching device 30a is switched from its left to its right position,

2. the valve 20 is opened,

3. the valve 35 is opened,

4. the valve 32a is closed,

5. if the switching device / is not already in its right position, it is switched to this and

6. a signal (light or sound) is transmitted to an observer standing at 14a to induce him to read or record the displays on the counting mechanism of the connected feed and dosing system.

When the contact a is depressed, the raw meal level in the container 17 is at H as previously indicated, and stands the pointer of the instrument 22 also points to H. The opening of the valves 20 and 351 the given position of the switching device 36 and set the closure of valve 32a

+) as stated

309808 / DÖ3Ü

ensure that all of the flour to be conveyed to the furnace connected to the pipe 15a is out of the container 17 is coming; the product level in the container will therefore begin to decrease, although at the same time Eohmehl passed through the container the Eohr 16a is supplied.

The material level in the container 17 will continue to fall, since raw meal emerges from it along the aforementioned path ending at 15a. At the same time, flour is fed from the supply container 10 ¹ through the pipe 31b via 15b to the other furnace. '. .

When the good level has dropped to level L (lower level), the pointer of the instrument 22 at the same time has reached the corresponding mark L, electrical contacts are actuated with the following effect:

1. "Transmission of a light or sound signal that the observer at 14a the display of the counter for the relevant Read or record time,

2. the valve 20 is closed,

3. the valve 35 is closed and

4. the valve 32a is opened.

The above switch causes both weighing and dosing devices 14a and 14b for direct conveyance from the supply container 10 'as before the initiation of the test weighing. However, the operating conditions are not entirely normal, since the container 17 must first fill up (up to Mark H) to be ready for test weighing again.

The container is filled because the valves 20 and 35 are now open and the container 17 is still open

./16 309808/0930

is supplied through line 16a. At the same time increases the product level in the container, and if the pointer of the instrument 22 moves to the right; if then H in the container and is reached on the instrument, electrical contacts are actuated, which switch over the switching device 30a from its right to its left position, thereby restoring completely normal operating conditions and a renewed examination weighing earlier or later, if desired, either again from 14a or can be started from 14b.

The observer at the weighing and dosing device 14a draws the first pouring result read from the last Result from, the difference thus obtained being the amount of raw meal that was dosed by the device while the good level in the feed container 17 of H (upper level) moved to L (lower level). This movement of the good level and the pointer of the instrument 22 corresponds to the delivery a certain number of tons from the weigh bin 17; and this amount must be the same as that dosed by device 14a. If the two quantity displays do not work match, the dosage is incorrect and the device 14a has to be readjusted, since the with the help the static weighing performed of the weigh bin 17 is much more accurate than the dynamic weighing to be performed the weighing and dosing device 14a is capable.

Of course, the container 17 can also with regard to the plant in Pig. 3 with a water jacket 17 '' be equipped for the purpose described in connection with FIG.

./17 309808/0930

Claims (1)

Claims Procedure for intermittent testing whether a continuous working weighing or dosing device is correctly set for a material mass in which "at Normal operation material is introduced into a closed circle, the material is moved internally in a circulating way, where a part · of the material out of the circle of a • continuously working weighing or dosing device is fed to the extent with which the device operates, and the remainder of the material through a Storage is passed through and continues to circulate, characterized by interruption of the supply the material mass to the closed circuit and determination of the extent at which the continuously, working Weighing or dosing device removes material from the ■ closed circuit, and thus the operational dimensions of the device by making the acceptance the weight of the material in the closed loop within a known time. 2. The method according to claim 1, characterized in that the memory is a weighing container that is used to determine the decrease in material weight is weighed in the closed loop. 3. The method according to claim 1, characterized in that the entire circle is weighed to determine the decrease in material weight in the closed circle. ./18 309808/0930 A method according to any one of the preceding claims, characterized in that the amount of material in The closed circuit is conveyed upwards to the continuously working weighing or dosing device to be fed while the rest of the material falls into the accumulator. Apparatus for carrying out the method according to any one of the preceding claims, characterized by a closed circuit for the material mass and controllable means (5, 6, 7) for feeding the mass of material to the closed circuit, a conveyor (11) in a closed circuit, by means of which the material can be fed to a supply head (13) via which it can be fed to a weighing or dosing device (14-), a chute (16) with a memory (17), over the superfluous material from the supply head (13) to Bottom of the conveyor (11) is retractable, means for weighing (21) at least that in the part of the closed Circle-forming memory (17) located material and the output of the weighing means (21) for simultaneous Control of the supply of the material mass to the closed circle, so that when the material weight drops at a predetermined lower limit the material feed to the closed circuit started and at If the material weight increases to an upper limit, the material feed to the closed circuit is stopped and an indicator (22) of the weight of at least the memory forming part of the closed circuit (17) located material, so that the decrease in material weight in a closed loop in a given -Time is determinable. 309808/0930 6. Apparatus according to claim 51, characterized in that that the lower end of the conveyor (11) protrudes into a supply container (10), where it is eggasse with material is loadable, both the controllable means (5, 6, 7), which the fresh material mass in a closed circle, as well as the chute (16) from the memory (17) into this supply container (10) empty. 7. Apparatus according to claim 5 or 6, characterized in that that the supply container (10) is equipped with a first level indicator (23) arranged in this way is that this is a signal to close a valve (20) in the chute (16) at the bottom of the store (17) releases when the supply container (10) is full is. 8. Device according to any of the. Claims 5 "to 7" thereby characterized in that the supply container (10) is provided with a second level indicator (24-) arranged in this way. is equipped that this emits a signal that the controllable Llittel (5 »6, 7) for the supply of fresher Material mass to the supply container (10) out of order sets when the level of material mass-in the supply container (10) reached the second indicator level. 9. Apparatus according to claim 8, characterized in that the second indicator (24) is higher than the first indicator (23) is arranged. 10. Device according to any one of claims 5 "° is %, characterized in that the V / iegemittel 7 / iegeelemente (21) on which at least the storage part of the closed circuit is supported. ./20 309808/0930 11. Device according to any one of claims 5 "to 9, characterized in that the memory (17) »the supply container (10), the continuously working Weighing or dosing device (14) and the conveyor (11) built into a common frame (26 to 29) which rests on the weighing elements (21) which work as weighing means. 12. Device according to any one of claims 5 "to 10, characterized in that a casing (17 ¹¹ ) surrounds the reservoir (16) and means for filling and emptying the casing (17 ¹¹ ) & it water and for weighing the amounts from the casing ( 17 ¹¹ ) the amount of water discharged is provided. 1Y. Device according to any one of claims 5 to 12, characterized in that working under the fortlnufond Weighing or dosing device (14) a funnel (18) for collection from the weighing or dosing device (14) overflowing material mass is provided, which leads into the memory (16). 14. The device according to any one of claims 5 "to 13, characterized in that the memory (17) is connected in the closed circuit in parallel with a memory (17 ¹ ) which is used to receive and pass material mass outside the test intervals and means to include the memory (17 ¹ ) in the system for the individually to be performed testing of several continuously working weighing and dosing devices (14a, 14b) are provided. 309808/0930